Simple technique for representing slots in cavities

Determining the coupling of electromagnetic fields into cavities via slots can be complex. This letter presents a simple technique of achieving this. The method utilises a superposition of coupling via a series of circular apertures that represent the equivalent slot. The series of apertures are all transposed to single position allowing the slot to be represented by a single circular aperture. A model for coupling via a slot is realised using intermediate level circuit modelling that yields credible results and is validated against a transmission line matrix model.